Engine control system

Abstract

For an internal combustion engine with a supercharger, a slip of the driven wheel is controlled by reducing torque of the engine, when the extent of the slip becomes large in relation to a road surface. When the running status of the engine exists in a non-supercharging region, the slip is controlled by at least one of operations for reducing the amount of fuel to be supplied to the engine and for retarding the timing of ignition (first slip control). On the other hand, in a supercharging region, the slip is controlled by lowering the pressure to be supercharged (second slip control). In a transient period of time when the running status of the engine is caused to shift from the non-supercharging region to the supercharging region when the first slip control is being conducted in the non-supercharging region, the first slip control is allowed to be continued until the slip is caused to be converged, in place of the second slip control.

What is claimed is: 
     
       1. Ah engine control system for an internal combustion engine with a supercharger so adapted as to implement a supercharging operation having a running status by supplying intake air; comprising: a supercharging-region determining means for determining a supercharging region on the basis of a predetermined condition;   a supercharging-operation controlling means for controlling a supercharging operation by implementing said supercharging operation by said supercharger when said supercharging region is determined by said supercharging-region determining means and by suspending said supercharging operation when said running status is determined thereby to be in a non-supercharging region;   a slip detecting means for detecting a slip of a driven wheel driven by said engine relative to a road surface;   a first slip control means for reducing torque of the engine by conducting at least one operation for ceasing the supply of fuel to the engine and for retarding the timing of ignition when the slip is detected by said slip detecting means in the non-supercharging region determined by said supercharging-region determining means;   a second slip control means for reducing the torque of the engine by controlling said supercharger so as to lower a pressure to be supercharged prior to the control of the slip by said supercharging-operation controlling means when said slip is detected by said slip detecting means in the supercharging region determined by said supercharging-region determining means; and   a control continuing means for continuing a control operation for controlling the slip by said first slip control means during a transient period of time until said supercharging operation is begun after said running status has been shifted into said supercharging region from said non-supercharging region during the control by said first slip control means.   
     
     
       2. An engine control system as claimed in claim 1, wherein said control continuing means is arranged to allow said first slip control means to continue the control of the slip until the time when the slip has been converged and no slip is detected by said slip detecting means. 
     
     
       3. An engine control system as claimed in claim 2, wherein said control continuing means is arranged to suspend an operation for supercharging by said supercharger prior to operations by said supercharging-operation controlling means and said second slip control means during said transient period of time when the slip is being controlled by said first slip control means. 
     
     
       4. An engine control system as claimed in claim 3, wherein the control by said supercharging-operation controlling means is begun after the slip of the vehicle has been converged and the control by said control continuing means has been released. 
     
     
       5. An engine control system as claimed in claim 1, wherein said predetermined condition is a running status of the engine. 
     
     
       6. An engine control system as claimed in claim 5, wherein: said running status of the engine is a pressure of intake air; and   said supercharging-region determining means is arranged to determine said supercharging region when the pressure of intake air is equal to or greater than a predetermined value.   
     
     
       7. An engine control system as claimed in claim 1, Wherein the slip is controlled by said first slip control means by reducing an amount of fuel to be supplied to the engine and retarding a timing of ignition. 
     
     
       8. An engine control system as claimed in claim 1, wherein said supercharging-operation controlling means is arranged to control the pressure to be supercharged so as to reach a predetermined target pressure to be supercharged. 
     
     
       9. An engine control system as claimed in claim 8, wherein said predetermined target pressure is set on the basis of the number of engine revolutions and an engine load as parameters. 
     
     
       10. An engine control system as claimed in claim 1, wherein the slip is controlled by said second slip control means so as to lower the pressure to be supercharged at a greater rate as the extent of the slip detected by said slip detecting means becomes larger. 
     
     
       11. An engine control system as claimed in claim 1, wherein the slip is controlled by said first slip control means so as to reduce the amount of the supply of fuel or to retard the timing of ignition at a greater rate as the extent of the slip detected by said slip detecting means becomes larger. 
     
     
       12. An engine control system as claimed in claim 1, wherein: an intake passage of the engine is provided with a bypath bypassing said supercharger;   said intake passage is provided with a control valve for adjusting an extent of an opening of said bypath; and   the pressure to be supercharged is controlled by said control valve.   
     
     
       13. An engine control system as claimed in claim 12, wherein said control valve is controlled in the non-supercharging region by opening said bypath to its full extent. 
     
     
       14. An engine control system as claimed in claim 1, wherein the control of the slip by said first slip control means is inhibited during the control by said second slip control means. 
     
     
       15. An engine control system as claimed in claim 1, wherein said slip detecting means is arranged to detect a slip of the driven wheel on the basis of wheel speeds of the driven wheel and an undriven wheel.